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Biomedical subjects

L Peterson

Publications and source records attributed to L Peterson.

At least 73 records · Page 4Linked to original sources
PubMed1996

Genetic control of giant perivascular space formation in the thymus of NOD mice.

The immune system of NOD mice exhibits several anomalies, one being the intrathymic formation of giant perivascular spaces (PVSs) filled with mature thymocytes and some B-cells, intermingled within a network of extracellular matrix. The abnormal retention of thymocytes on their way to the periphery could have a profound impact on the nature of the exported cells and the regulation of autoimmune events. In the present study, we evaluated the appearance of this defect into F1 hybrids, the association with some of the known diabetes susceptibility loci (Idd genes) in a panel of NOD and reciprocal C57BL congenic strains, and the relative contribution of epithelial versus hematopoietic stroma. The analysis of F1 hybrid thymuses reveals a dominant expression of thymic giant PVS that is only marginally influenced by the outcross strain. Moreover, giant PVS expression in major histocompatibility complex (MHC) and Idd congenic mice is determined by the genetic background. All of the NOD congenics express the anomaly, irrespective of the Idd resistance alleles that have been introgressed, whereas none of the C57BL congenic mice present abnormal PVS. Finally, the expression of giant PVS in parental --> F1 bone marrow chimeras is predominantly controlled by the thymic NOD-derived hematopoietic microenvironment. In conclusion, the giant PVS formation in the NOD mouse thymus is a dominantly inherited anomaly associated with hematopoietic-derived tissue and with non-MHC genes. The exact contribution of PVS to the autoimmune process remains to be definitively established.

Animals↗
PubMed1996

Options in education for advanced trainees in isolated general practice.

BACKGROUND: Only a small number of remote solo doctors are needed each year to provide health care to remote communities. However, despite advances in the provision of appropriate training for intending rural doctors, the preparation of graduates for this kind of medical practice has received little attention. OBJECTIVE: To develop and evaluate an optional training unit within the Royal Australian College of General Practitioners Training Program, which provides trainee GPs with an opportunity to learn about remote medicine during training with the distant support of an experienced rural doctor. METHOD: A program of intensive educational support was developed and piloted with a group of nine GP in solo rural practices and compared to that provided to four GP trainees in standard advanced GP terms. Comparison was based on data collected in trainee logbooks and in questionnaires completed by trainees and supervisors. RESULTS: The solo trainees received equivalent duration of educational support through the use of communications technology and other distance education methods. The training unit will be trialed further and may remain an option within the Training Program.

Career Choice↗
PubMed1995

A new educational approach for supporting the professional development of third-year medical students.

This paper describes a new course designed to support the professional development of third-year medical students. The course runs through the clinical clerkships, and has several additional features: it includes a multidisciplinary faculty; it is centrally based in the medical school; it addresses students' values and attitudes in addition to their knowledge and skills; and it makes use of small-group learning methods, and faculty, student, and group continuity during the year. The curriculum, which addresses ethical, social, and communicative issues in medicine, plus the evaluation of students and of the course, are described.

Boston↗
PubMed1995

A developmental exploration of expectations for and beliefs about preventing bicycle collision injuries.

Investigated developmental and gender-related trends in 2nd, 5th, and 8th graders', undergraduates', and adults' reactions to simulated bicycle collisions. Recently, scientists have called for exploration of the developmental mechanisms that underlie childhood injury. Our laboratory has, in three separate studies, demonstrated age-related decreases in beliefs about the negative consequences of bicycle collision. These developmental decreases in the expected seriousness of outcome parallel age-related increases in injury risk. The present study examined two alternative explanations for cognitive differences that might be related to increased risk for bicycle injury with increasing age. Contrary to predictions, however, age and gender were unrelated to subjects' expectations for whether a collision would take place, be actively avoided, or fail to take place. Similarly, age and gender were unrelated to whether subjects believed they could remain safe, that safety equipment (e.g., helmets) would keep them safe, or that different behavior would keep them safe. Results fail to support these expectations and beliefs as alternative explanations to developmental and gender-related trends in bicycle injuries, and indirectly suggest the importance of children's beliefs about the seriousness of injury as a contributer to injury risk behavior.

Accidents, Traffic↗
PubMed1995

Parents' socialization of children's injury prevention: description and some initial parameters.

In a year-long participant observation study of remediative action following actual injury, 61 8- and 9-year-old children and their 27-46-year-old mothers wrote records and reported on more than 1,000 minor injuries in branching biweekly interviews. Mothers reported that 80.1% of injuries received no parent-initiated remediation, 14% received only a lecture, and less than 3% of injuries were followed by parental action. Children reported that 96.1% of their injuries were followed by no remediative action and recalled lectures after only 1.2% of injuries. Remediative action was related to type of child activity (e.g., unstructured play was followed by remediation more often than more purposive behavior) and to mother's affect (e.g., anger) and beliefs (e.g., that injury was the child's fault or due to rule violation). The parameters that influenced remediative consequences, and thus that may influence future injury, are discussed.

Accident Prevention↗
PubMed1995

On advancing behavior analysis in the treatment and prevention of battering: Commentary on Myers.

MYERS OFFERS AN IMPORTANT CHALLENGE TO BEHAVIOR ANALYSTS: eliminating the battering of women. In this commentary, we extend the conceptual model advocated by Myers, urge a bidirectional approach that focuses more on the battered woman and less on the battering man, caution against the indiscriminate use of marital therapy approaches, and argue that the most important contributions in the field may come from behavioral prevention rather than treatment interventions.

Journal Article↗
PubMed1995

Sweat gland carcinoma in a human immunodeficiency virus-infected patient.

Eccrine (sweat gland) carcinoma is a rare form of skin cancer that may be locally destructive. It is known to recur after resection and can metastasize to regional or distant lymph nodes. There have been two reported cases in association with patients immunocompromised as the result of organ transplantation (I. Penn: Prog Allergy. 37: 259, 1986). We report here the first case of sweat gland carcinoma in a patient infected with the human immunodeficiency virus.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Stereoselectivity and isotope effects associated with cytochrome P450-catalyzed oxidation of (S)-nicotine. The possibility of initial hydrogen atom abstraction in the formation of the delta 1', 5-nicotinium ion.

The stereochemical course of cytochromes P450 [P4501A1, P4502B1, P4502B4, and P450101 (P450cam)] catalyzed alpha-carbon oxidations of the cis-(Z)- and trans-(E)-5'-d1 diastereomers of (S)-nicotine has been examined. All enzyme preparations led to the stereoselective abstraction of the 5'-hydrogen atom trans to the pyridine ring with P450101 and human liver microsomal preparations displaying the highest (90%) and P4502B1 the lowest (67%) degree of stereoselectivity. No isotope effect was detected for any of the enzyme-catalyzed reactions, although the existence of an intrinsic isotope effect was inferred by the observation of an intramolecular isotope effect of 2-2.6 observed for the N-demethylation of (S)-N'-dideuteromethylnornicotine. Evidence for P450101-catalyzed N'-oxidation was sought but could not be found at higher than trace levels. These results, together with those obtained by computational methods, are interpreted in terms of an alpha-carbon oxidative pathway involving hydrogen atom abstraction rather than single electron transfer as the initiating event in the P450-catalyzed oxidation of (S)-nicotine to its delta 1',5'-iminium ion metabolite.

Animals↗
PubMed1995

[Autologous cartilage cell transplantation. The goal is pain relief and restored joint function].

Chondral and osteochondral damage is a common result of trauma to the joints. The capacity of cartilage to heal such damage is poor, and repetitive wear on joint surfaces that do not heal results in impaired joint function, which can culminate in full blown arthrosis. Thus, it is important to improve our knowledge of cartilage regenerative potential, and develop methods to forestall progression to arthrosis by promoting the early healing of cartilage damage. Autologous cartilage cell transplantation may be a mean of healing cartilage damage. A method of cultivating autologous chondrocytes for transplantation in the treatment of isolated damage to articular cartilage of the knee is presented in the article.

Cartilage↗
PubMed1994

Treatment of deep cartilage defects in the knee with autologous chondrocyte transplantation.

BACKGROUND: Full-thickness defects of articular cartilage in the knee have a poor capacity for repair. They may progress to osteoarthritis and require total knee replacement. We performed autologous chondrocyte transplantation in 23 people with deep cartilage defects in the knee. METHODS: The patients ranged in age from 14 to 48 years and had full-thickness cartilage defects that ranged in size from 1.6 to 6.5 cm2. Healthy chondrocytes obtained from an uninvolved area of the injured knee during arthroscopy were isolated and cultured in the laboratory for 14 to 21 days. The cultured chondrocytes were then injected into the area of the defect. The defect was covered with a sutured periosteal flap taken from the proximal medial tibia. Evaluation included clinical examination according to explicit criteria and arthroscopic examination with a biopsy of the transplantation site. RESULTS: Patients were followed for 16 to 66 months (mean, 39). Initially, the transplants eliminated knee locking and reduced pain and swelling in all patients. After three months, arthroscopy showed that the transplants were level with the surrounding tissue and spongy when probed, with visible borders. A second arthroscopic examination showed that in many instances the transplants had the same macroscopic appearance as they had earlier but were firmer when probed and similar in appearance to the surrounding cartilage. Two years after transplantation, 14 of the 16 patients with femoral condylar transplants had good-to-excellent results. Two patients required a second operation because of severe central wear in the transplants, with locking and pain. A mean of 36 months after transplantation, the results were excellent or good in two of the seven patients with patellar transplants, fair in three, and poor in two; two patients required a second operation because of severe chondromalacia. Biopsies showed that 11 of the 15 femoral transplants and 1 of the 7 patellar transplants had the appearance of hyaline cartilage. CONCLUSION: Cultured autologous chondrocytes can be used to repair deep cartilage defects in the femorotibial articular surface of the knee joint.

Adolescent↗
PubMed1994

Developmental patterns of expected consequences for simulated bicycle injury events.

Bicycle injuries follow a developmental pattern that differs from that of most injuries, where toddlers and individuals in young adulthood are most at risk. Children in late childhood and early adolescence appear most at risk for bicycle injuries. The present study of 2nd-grade, 4th-grade, 6th-grade, and undergraduate college students documented that after videotaped simulations of bicycle injury events, younger children anticipated greater injury severity and more fear than older children and adolescents. The potential influence of reduced expectations for injury with increasing age is described, and challenges are advanced for establishing the link between lowered injury expectancies and increased risky behavior.

Adolescent↗
PubMed1994

Integrating child injury and abuse-neglect research: common histories, etiologies, and solutions.

Research on injuries, the leading health threat to children in the United States, has been infrequent and badly fragmented. Research on unintentional injuries and research on abuse-neglect have similar histories, including recent rapprochement with behavioral interventions, and reveal similar etiologies for child injury. Further, recent studies document difficulties in discriminating between unintentional and abuse-neglect-related injuries. The areas also face similar methodological and conceptual challenges. Finally, the same interventions may prevent negative outcomes in both areas. A working model to summarize a more integrated approach to injury prevention is offered. Increasing societal awareness of the threat posed by injuries and strengthening mutually applicable strategies of injury prevention would be sought-after results of unifying efforts in these historically isolated arenas.

Caregivers↗